Convertible drilling tool



y 1932- J. B. DE COSTA CONVERTIBLE DRILLING TOOL Filed Feb. 28, 1950 2 Sheets-Sheet 1 awvenkoz John, B. 176 605 m,

July 19, 1932. J. B. DE COSTA CONVERTIBLE DRILLING TOOL 2 Sheets-Sheet 2 Filed Feb. 28, 1930 John 3. 17660520 Wifnedks;

artozmuz Patented July 19, 1932 UNITED STATES PATENT OFFICE Application filed February 28, 1930. Serial No. 432,163.

My invention relates to rotary boring tools for sinking oil, gas and other wells, and the principal object of the invention is to provide a tool of this character with a plurality of L3) interchangeable bits, some of which are adapted to operate in the softer formations as soils, clays and the like, others in the intermediate formations such as gumbo, sandy shales and similar stratas, and others in hard ,10. 1fi 1)(rmations as the limestones, quartz and the The present invention is an improvement over the convertible drilling tool for'which U. S. Letters Patent No. 1,733,336 were 15 granted to me October 29, 1929, and consists of certain new and novel features hereinafter described and more particularly pointed out in the claims.

' In the accompanying drawings:

Fig. 1 shows a side view of the stock provided with rotary rock cutters and; other equipment.

Fig.2 is a side elevation of a central fit ting, and a pilot drill adapted to be used with said fitting. v

Fig. 3 is a perspective view of one of a plurality of brackets employed in carrying out the invention.

Fig. 4 is an end view of. one of a plurality of rotary rock cutters.

Fig. 5 is an inverted plan view of the drill body with the cutters and other equipment removed.

Fig. 6 is a side elevation of one of a plurality of reamers and its step bearing.

Fig. 7 is a longitudinal section on line 7-7 ofFig. 1.

1 Fig. 8 is an inverted plan view of the parts 40 shown by Figs. 1 and 7.

. Fig. 9 is an inverted plan view of the drill body equipped with disk cutters.

Fig. 10 is an inverted lan view of the drill body equipped with sh tail bits.

Fig. 11 is a cross section taken on line 11-11 of Fig. 7.

Fig. '12 is a side view of one of the rotary disk cutters.

Fig. 13 is a perspective view of one of the fish tail bits. Y

Referring in detail to the different parts,

2 designates the drill body which consists of a stock 4 provided with a shank 6 adapted to be threaded into the lower end of an ordinary drill stem, not shown. The stock 4 is reinforced with a plurality of radially 65 disposed ribs 8 which are spaced apart to leave intervening channels 10 through which mud and other cuttings may pass when being flushed from the well.

The under side of the stock 4 and the ribsv 8 are provided with radially disposed dove-tailed grooves 12 for the reception of dove-tailed tongues? 14 on the upper portions of a plurality of brackets 16 provided at their lower portions with stub shafts 18 upon which rotary cutters 20 and 21 are adapted to be mounted. The tongues 14 are removably secured in the grooves 12 by suitable means such as screws 19. The rotary cutters 20 are tapered towards one end and provided with peripheral teeth 22 so that they may prove effective in cutting through rock and other hard formations. The rotary cutters 21 are also tapered towards one end and provided with a plurality of circular cutting edges 24, so that they may cut through sandy shales, gumbo and other formations of intermediate hardness.

The stub shafts 18 are assisted in supporting the rotary cutters by means of a central fitting 26 having a lower downward flaring portion which is rectangular in cross section and provided with radially disposed upwardly inclined stub shafts 28 upon which the inner ends of the respective rotary cutters are adapted to be journaled. Reinforcing elements such as screws 29 are placed in axial openings in the bearings 18 and threaded in axial ducts 31 in the bearings 28 to connect said bearings so that they will tend to brace each other and the depending legs 33 of the brackets 16. The central fitting 26 has a c1rcular upper portion 30 adapted to be threaded in an opening 51 formed centrally in the lower end of the drillstock 1. Saidfitting 26 also has a shoulder 32 adapted to contact the bottom of the stock at and thus act as a stop for preventing further inward movement of the o0 circular portion 30 after the stub shafts 28 1 become axially alined with the respective stub shafts 18. A concentrically disposed annular row of teeth 34 are formed on the lower end of the fitting 26 for cutting out material between the rotary cutters and 21. When desired a conical pilot bit 36 may \be threaded into the lower end of the fitting 26 to uncover the annular row of teeth 34.

-38 designates a plurality of fishtail bits for operating in soils and other relatively softformations. The bits 38 are provided at their upper portions with dove-tailed tongues which are adapted to fit into the grooves 12 after the tongues 14 of the brackets 16 have been removed fr m said grooves 12. Each tongue 40 has a transverse hole 41 for the passage of the respective screw 19 which holds said tongue in its groove 12. A central fitting 26 with an annular row of teeth 34 is used with the fish-tail bits 38. Ducts 43 extend through the fish-tail bits 38 and communicate with the ducts 44 in the drill body 2 for delivering water to the cutting edges of said bits.

In order that water may be readily introduced into the bottom of the well for flushing out the cuttings and preventing undue wear of the bits and rotary cutters while in operation, I provide the drill body 2 with a vertically the ducts 44 and all of which communicate with the bore of the hollow drill stem, not shown, through which the water is introduced in the usual manner. The lower portion of the central duct 42 communicates with a duct 46 extending centrally through the fitting 26 and communicating with the branch ducts 31 and branch ducts 48 which latter lead to the sides of the fitting'26 at a point just above the rotary cutters so that water discharged through said ducts 48 may prevent the cutters from becoming clogged with mud and other dbris. The branch ducts 31 communicate with smaller ducts 50 which extend transversely through the stub shafts 18 and 28 for discharging a portion of the water between said stub shafts and the rotary cutters for the purpose of preventing overheating and undue wear of the contacting parts. The brackets '16 are provided with ducts '49 which are i ada ted to communicate with the ducts 44 so t at water may be discharged upon the rotary cutters in addition to the water discharged from the branch ducts 48.

Referring again to the ribs 8 it will be noted that they have vertically disposed cavities 56 for the reception of reamers 58, provided at their ends with stub shafts 60 the upper ones of which are journaled in recesses in the pillars while the lower ones are journaled in step bearings 62. Said step bearings 62 fit in the lower portions of the cavities 56 and are provided at their lower sides with grooves 64 for the recepdisposed duct 42 in addition to tion of the upper ends of the tongues 14 or will also be understood that a core of the different formations may-be obtained whenever desired by removing the pilot bit 36 and permitting the teeth 34 of the central fitting to cut the material which is then forced up to the surface through the ducts 46, 42 and the hollow drill stem.

In addition to the cutters shown and'described, I reserve the right to use such other cutters as may be employed to advantage with my drilling tool. I also reserve all rights to such other changes and modifications as properly fall within the spirit and scope of the invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent, is:

1. A device of the character described comprising a drill body having three or more radial dovetailed grooves in its lower end, reinforcing ribs arranged around said body and spaced apart to leave intervening channels, the undersides of said ribs having dovetailed grooves communicating with those in the body, brackets having dovetailed tongues for fitting into said grooves, bearings on said brackets, and rotary cutters mounted upon said bearings.

2. A device of the character described consisting of a drill body having a duct extending longitudinally therethrough, a central fitting connected to the lower end of said body and having a duct communicating with the first-mentioned duct, an annular row of teeth on the lower end of said fitting, a pilot bit adapted to be threaded into the lower end of the duct in said fitting, a plurality of bearings projecting radially from said fitting and having ducts extending axially and transversely therethrough and communicating with the duct in said fitting, cutting tools adapted to be mounted upon said bearin s, and other bearings connected to the drill body and adapted to cooperate with the first-mentioned bearings in supporting said cutting tools.

3. A device of the character described consisting of a drill body, a central fitting having a cylindrical upper portion threaded into said body and a lower downwardly flaring portion'which is rectangular in cross section and has a bearing inclined upwardly from each side thereof, conical Shaped cutting tools journaled upon said bearings and having their smaller terminals abutting the flaring sides of the central fitting, and other bearings removably connected to the drill body and coacting with the first-mentioned hearings in supporting said cutters.

In testimony whereof I afiix my signature.

JOHN B. DE COSTA 

